Drafting aid

ABSTRACT

In a drafting aid, at least one transparent pattern board, a pattern of rabbets on the upper part of the board, means on the underside of the board for securing thereto sketching paper having thereon a rough sketch to be formalized, a pantograph having a tracing point running inside of the rabbet, marking means supported by the pantograph and simultaneously movable with the tracing point and a sheet of paper under the marking means upon which the marking means imprints a formal drawing of the sketch secured to the underside of the pattern board. The aid is particularly useful for drawing transistorized circuits from rough circuit diagrams.

United States Patent Karel [54] DRAFTING AID [72] Inventor: Havel Karel, PO. Box 66, Station M Toronto 21, Ontario, Canada [22] Filed: Feb. 25, 1971 211 Appl. No.: 118,710

[52] US. Cl. ..35/26, 33/25 B [5l] Int. Cl. ..B43l 13/10 [58] Field of Search ..35/26; 33/1 K, 23 R, 23 G,

33/23H, 25 R, 25 B 2,958,948 11/1960 Dunkelberger ..35/26X 1 Aug. 1, 1972 Primary Examiner-Harland S. Skogquist 5 7] ABSTRACT In a drafting aid, at least one transparent pattern board, a pattern of rabbets on the upper part of the board, means on the underside of the board for securing thereto sketching paper having thereon a rough sketch to be formalized, a pantograph having a tracing point running inside of the rabbet, marking means supported by the pantograph and simultaneously movable with the tracing point and a sheet of paper under the marking means upon which the marking means imprints a formal drawing of the sketch secured to the underside of the pattern board. The aid is particularly useful for drawing transistorized circuits from rough circuit diagrams.

8 Claims, 10 Drawing Figures DRAFTING AID This invention relates to a drafting aid which is particularly useful for making drawings of transistorized circuits employing various symbols.

Heretofore, pantographs have been used mainly for making exact copies of an original on a larger or a smaller scale. They have also been used for constructing composite pictures from individual pieces adapted to be arranged on a predetermined order to provide a composite pattern. A device for doing this is described in U.S. Pat. No 2,176,797 to J. Y. Henry. It has also been suggested in U.S. Pat. No 2,543,998 to combine a pantograph with rotatable discs having different facial features and which can be traced through an opening in a superimposed opaque disc. However, as far as I know, the art has not provided a pantograph device which makes it possible to trace a professional-type -type drawing from a rough sketch.

Accordingly, one of the objects of the invention is to provide a device of the type described which can be easily manipulated even by inexperienced draftsmen to form a variety of formal drawings using reproducing means.

Another object of the invention is to provide a simple and inexpensive device for aiding draftsmen.

With these and other objects in view, the invention consists in certain novel features of construction, combination and arrangement of parts which will be evident as the present description proceeds particularly when taken together with the accompanying drawing wherein:

FIG. 1 is a top plan view of the device of the inventlon.

FIG. 2 is a top plan view of sketching paper with a rough sketch.

FIG. 3 is a top plan view of the transparent board.

FIG. 4 is a side view of the board of FIG. 3 showing also the pantograph point and the means for securing the sheet of FIG. 2.

FIG. 5 is a detailed cross-section of the board of FIG. 3 showing a rabbet with the pantograph point.

FIG. 6 is a detailed view of part of the drawing shown in FIG. 2 and marked B on FIG. 2.

FIG. 7a is an elevation of means for leading the point of the pantograph.

FIG. 7b is a sectional view of the means of FIG. 7a.

FIGS. 8a and 8b are the same as FIGS. 7a and 7b for other means.

In the above drawing the same reference numerals identify the same or like parts or features.

Referring to FIG. 1, 10 designates a pantograph consisting of four bars 12, l4, l6, l8 movably connected at points 20, 22, 24 and 26. Pen or the like, 28 is secured to the underside of the extremity of bar 12. A tracing point 30 is mounted under point 26 above the sheet 32 on which the final or formal drawing will be made. A pattern board of transparent preferably plastic material 34 lies under pen 28. As shown in FIG. 4, a hook 36 or other fastening means is provided on the underside of board 34 for securing a sheet of sketching paper 38 hearing a universal pattern such as lined squares.

As shown in FIG. 5, the top of board 34 has a plurality of rabbets 40 pressed or engrained thereon and adapted to receive pen 28 therein. To avoid problems of shaking straight lines caused by the point P running off the crossroads of board 34, a ski-like attachment 42 can be provided for leading off the point P or two transparent boards can be used; one with vertical lines and the other with horizontal lines. Whichever means is used, all the horizontal lines of the sketch will be drawn and then all the vertical lines. For this, number 42 will be turned vertically or the boards will be changed from the horizontal one to the vertical one. To make circles, a circularly-shaped ski attachment 44 can be used.

As an example of the invention, a transistorized circuit was drawn.

This involves the use of sketching paper 38 on which is imprinted a pattern for the universal drawing of transistorized circuits. A transparent board with the same pattern must be used. A rough sketch of the desired circuit is drawn by hand on paper 38 using only existing lines. Paper 38 is then attached to the bottom of board 34 on book 36. Board 34 is transparent and has thereon engraved the same pattern as that on sheet 38 and the two are placed in register. The sketch can be seen through the transparent board. Next tracing point 28 is moved inside the rabbets along the lines of the sketch. Pen 30 then draws, in some suitable scale, the final drawing. All direct lines are absolutely straight regardless of the fact that the sketch was only rough because all lines are traced along the pattern lines and all symbols are made according to the pattern. Thus, in FIG. 5, line is a correct line while line 52 is an improper line.

Naturally it is possible to use several pattern boards instead of one. One pattern board may have a grid of rectangular lines, another will have only symbols for transistors, still others will have different components. Everything will be printed together on the sketching paper. This will be used as follows. The rough sketch drawn on the sketching paper is secured under board No. l (which has components and all the components are drawn which are found on the sketch). Then, the sketch is secured to another board, say board 2 which has a pattern of rectangular lines and all the lines found on the sketch are drawn. I

The present drafting aid is useful for mechanical and civil engineering drawings as well as for drawing electrical circuits.

Suitable plastic material for making board 32 are polymethocrylate, polyvinyl chloride, polystyrene and polyethylene.

What I claim is:

1. In a drafting aid, at least one transparent pattern board carrying thereon a pattern of rabbets on the upper part thereof; securing means on the underside of the board carrying sketching paper having thereon a rough sketch to be formalized; a pantograph having a tracing point running inside the pattern of rabbets above the board; marking means supported by the pantograph and simultaneously movable with the tracing point; a sheet of paper under the marking means upon which the marking means imprint a formal drawing of the sketch on the sketching paper.

2. Drafting aid according to claim 1, wherein both the board and the sketching paper have the same pattern of rabbets and lines, respectively.

3. Drafting aid according to claim 1, wherein the pattern board is of polymethocrylate.

4. Drafting aid according to claim 1, wherein the pattern board is of polyvinyl chloride.

5. Drafting aid according to claim 1, wherein the are provided on the tracing point for leading off the transparent board is of polystyrene. same.

6. Drafting aid according to claim 1, wherein the Drafting aid ac o ding to Claim 7, wherein the board is of polyethylene, means are a ski-like attachment.

7. Drafting aid according to claim 1, wherein means UNITED STATES PATENT OFFICE QE'HHQATE OF CQEUHN Patent No. 3,680,226 Dated Aiggust l, 1972 Inventor(s) Karel Havel It. is certified that error appears in the above-identified patent and that said Letters Patentare hereby corrected as shown below:

On the cover sheet [72] the inventors name should read KAREL HAVEL Signed and sealed this 19th day of December 1972.

(SEAL) Attest:

EDWARD M.FLETCKER,JR. ROBERT GOTTSCHALK v Attesting Officer Commissioner of Patents FORM PC4050 (10439) USCOMM-DC 6O376-P69 U.5. GOVERNMENT PRlNTING OFFICE: 19.9 0"366'33. 

1. In a drafting aid, at least one transparent pattern board carrying thereon a pattern of rabbets on the upper part thereof; securing means on the underside of the board carrying sketching paper having thereon a rough sketch to be formalized; a pantograph having a tracing point running inside the pattern of rabbets above the board; marking means supported by the pantograph and simultaneously movable with the tracing point; a sheet of paper under the marking means upon which the marking means imprint a formal drawing of the sketch on the sketching paper.
 2. Drafting aid according to claim 1, wherein both the board and the sketching paper have the same pattern of rabbets and lines, respectively.
 3. Drafting aid according to claim 1, wherein the pattern board is of polymethocrylate.
 4. Drafting aid according to claim 1, wherein the pattern board is of polyvinyl chloride.
 5. Drafting aid according to claim 1, wherein the transparent board is of polystyrene.
 6. Drafting aid according to claim 1, wherein the board is of polyethylene.
 7. Drafting aid according to claim 1, wherein means are provided on the tracing point for leading off the same.
 8. Drafting aid according to claim 7, wherein the means are a ski-like attachment. 